/// <devdoc>
/// Computes the calculated value given a raw counter sample.
/// </devdoc>
public static float ComputeCounterValue(CounterSample oldSample, CounterSample newSample)
{
int newCounterType = (int)newSample.CounterType;
if (oldSample.SystemFrequency == 0)
{
if ((newCounterType != NativeMethods.PERF_RAW_FRACTION) &&
(newCounterType != NativeMethods.PERF_COUNTER_RAWCOUNT) &&
(newCounterType != NativeMethods.PERF_COUNTER_RAWCOUNT_HEX) &&
(newCounterType != NativeMethods.PERF_COUNTER_LARGE_RAWCOUNT) &&
(newCounterType != NativeMethods.PERF_COUNTER_LARGE_RAWCOUNT_HEX) &&
(newCounterType != NativeMethods.PERF_COUNTER_MULTI_BASE))
{
// Since oldSample has a system frequency of 0, this means the newSample is the first sample
// on a two sample calculation. Since we can't do anything with it, return 0.
return(0.0f);
}
}
else if (oldSample.CounterType != newSample.CounterType)
{
throw new InvalidOperationException(SR.GetString(SR.MismatchedCounterTypes));
}
if (newCounterType == NativeMethods.PERF_ELAPSED_TIME)
{
return((float)GetElapsedTime(oldSample, newSample));
}
NativeMethods.PDH_RAW_COUNTER newPdhValue = new NativeMethods.PDH_RAW_COUNTER();
NativeMethods.PDH_RAW_COUNTER oldPdhValue = new NativeMethods.PDH_RAW_COUNTER();
FillInValues(oldSample, newSample, oldPdhValue, newPdhValue);
LoadPerfCounterDll();
NativeMethods.PDH_FMT_COUNTERVALUE pdhFormattedValue = new NativeMethods.PDH_FMT_COUNTERVALUE();
long timeBase = newSample.SystemFrequency;
int result = SafeNativeMethods.FormatFromRawValue((uint)newCounterType, NativeMethods.PDH_FMT_DOUBLE | NativeMethods.PDH_FMT_NOSCALE | NativeMethods.PDH_FMT_NOCAP100,
ref timeBase, newPdhValue, oldPdhValue, pdhFormattedValue);
if (result != NativeMethods.ERROR_SUCCESS)
{
// If the numbers go negative, just return 0. This better matches the old behavior.
if (result == NativeMethods.PDH_CALC_NEGATIVE_VALUE || result == NativeMethods.PDH_CALC_NEGATIVE_DENOMINATOR || result == NativeMethods.PDH_NO_DATA)
{
return(0);
}
else
{
throw new Win32Exception(result, SR.GetString(SR.PerfCounterPdhError, result.ToString("x", CultureInfo.InvariantCulture)));
}
}
return((float)pdhFormattedValue.data);
}
/// <devdoc>
/// Computes the calculated value given a raw counter sample.
/// </devdoc>
public static float ComputeCounterValue(CounterSample oldSample, CounterSample newSample) {
int newCounterType = (int) newSample.CounterType;
if (oldSample.SystemFrequency == 0) {
if ((newCounterType != NativeMethods.PERF_RAW_FRACTION) &&
(newCounterType != NativeMethods.PERF_COUNTER_RAWCOUNT) &&
(newCounterType != NativeMethods.PERF_COUNTER_RAWCOUNT_HEX) &&
(newCounterType != NativeMethods.PERF_COUNTER_LARGE_RAWCOUNT) &&
(newCounterType != NativeMethods.PERF_COUNTER_LARGE_RAWCOUNT_HEX) &&
(newCounterType != NativeMethods.PERF_COUNTER_MULTI_BASE)) {
// Since oldSample has a system frequency of 0, this means the newSample is the first sample
// on a two sample calculation. Since we can't do anything with it, return 0.
return 0.0f;
}
}
else if (oldSample.CounterType != newSample.CounterType) {
throw new InvalidOperationException(SR.GetString(SR.MismatchedCounterTypes));
}
if (newCounterType == NativeMethods.PERF_ELAPSED_TIME)
return (float)GetElapsedTime(oldSample, newSample);
NativeMethods.PDH_RAW_COUNTER newPdhValue = new NativeMethods.PDH_RAW_COUNTER();
NativeMethods.PDH_RAW_COUNTER oldPdhValue = new NativeMethods.PDH_RAW_COUNTER();
FillInValues(oldSample, newSample, oldPdhValue, newPdhValue);
LoadPerfCounterDll();
NativeMethods.PDH_FMT_COUNTERVALUE pdhFormattedValue= new NativeMethods.PDH_FMT_COUNTERVALUE();
long timeBase = newSample.SystemFrequency;
int result = SafeNativeMethods.FormatFromRawValue((uint) newCounterType, NativeMethods.PDH_FMT_DOUBLE | NativeMethods.PDH_FMT_NOSCALE | NativeMethods.PDH_FMT_NOCAP100,
ref timeBase, newPdhValue, oldPdhValue, pdhFormattedValue);
if (result != NativeMethods.ERROR_SUCCESS) {
// If the numbers go negative, just return 0. This better matches the old behavior.
if (result == NativeMethods.PDH_CALC_NEGATIVE_VALUE || result == NativeMethods.PDH_CALC_NEGATIVE_DENOMINATOR || result == NativeMethods.PDH_NO_DATA)
return 0;
else
throw new Win32Exception(result, SR.GetString(SR.PerfCounterPdhError, result.ToString("x", CultureInfo.InvariantCulture)));
}
return (float) pdhFormattedValue.data;
}
